Depression which interferes with maternal role functioning occurs in 10 to 15 percent of postpartum women. This disorder causes personal and family suffering at a time when adaptation to the tasks of parenthood is critical. Rapid provision of effective treatment is imperative to prevent the consequences of maternal illness. However, there are no controlled pharmacologic treatment studies of women with postpartum major depression (PPMD). The purpose of this study is to conduct a double-blind, randomized clinical trial of sertraline (SERT) compared to nortripytyline (NTP) for the treatment for PPMD. The proposed study is a fixed-dose, 8 week clinical trail. The hypothesis is that a SERT tnan to NPT as defined by measures of symptom reduction and psychosocial function. Secondary hypotheses are: 1) the side effect burden of women treated with SERT will be less than with NTP; 2) depressed women with aggressive obsessional thoughts will respond more favorably to SERT; and 3) specific clinical variables will be associated with drug response (depression severity, personality disorder, marital disaffection, and psychosocial problems).